Apparatus for controlling drafts



March 21, 1-939. I H. HAGEN 2,151,512

v APPARATUS FOR CONTROLLING DRAFTS Filed' March 4, 195s 5 Sheets-Sheet 1 E 2 M29 17 f /5 Q #5 a 26 4/ 2-; v g 22a 52 INVENTOR HILMAR R: HAGEN paw I.

ATTORNEY March 21, 1939. .H. R. HAGEN- 2,151,512

APPARATUS FOR CONTROLLING D RAFTS Filed-March 4, 1938 -3 Sheets-Sheet 2 INVENTOR ATTO R N EY H: HAGEN APPARATUS FOR CONTROLLING mum's Filed March 4, 193a a shets-sheet 3 55 INVENTOR ATTO R N EY HILMAR R. HAGEN ia- M to increase the available natural draft when the Patented Mar.21', 1939 APPARATUS FOR CONTROLLING nasr'rs Hilmar R. Hagen, Pottsville, Pa., assignor to The Philadelphia and Reading Coal and Iron Company, Philadelphia, Pa., a corporation of Pennsylvania Application March 4, 1938, Serial No. 193,838

21 Claims.

and damper construction.

It is an object of my invention to provide apparatus for controlling two or more streams of air and/or gas in a solid-fuel heater.

It is a further object of this invention to provide means for automatically regulating dampers for the foregoing object in such a manner that a floating or varying control is obtained in order to reduce under and overheating.

A further object of my invention is to provide automatic damper regulation for streams of air or other gas in a solid-fuel heater in which air heated by the fire-pot is released to the chimney fire is checked.

It is a further object of my invention to provide novel apparatus for controlling such streams of air and/or gas, either as they enter the heating apparatus or at the point of removal therefrom.

While'the features of my invention are not limited to use in connection with radiation heaters, they find particular utility in combination with draft control apparatus such as shown and described in the application of Harold J. Rose,

Serial No. 78,549, filed May 8, 1936.

My invention will be described in connection with such heating apparatus and further advantages and objects of the invention will be more apparent from a consideration of the em-,

bodiments illustrated in the drawings, in which Figure 1 is a vertical cross section through approximately the center of a radiation heater, with a portion of the apparatus shown in elevation.

Figure 2 is a vertical cross section through approximately the center of the outlet conduits and damper for withdrawing air and/or products of combustion from a heating apparatus and illusof the apparatus" shown Figure 4 is a vertical cross sectional view of the thermostatic operating mechanism taken on the line 4-4 of Figure 3.

Figure 5 is a vertical cross section similar to horizontal cross sectional view Figure 2, but illustrating a further modification of the apparatus.

Figure 6 is a horizontal cross section taken on the line 6-6 of Figure 5 and broken away to show the construction of the thermostatic devices.

Figure 7 is a vertical cross section of a detail taken on the line 'I of Figure 6;

With reference to the embodiment of the in-' vention shown in Fig. 1, numeral Hi indicates a shell which, together with a grate H, defines a fire-pot for the combustion of solid-fuel. Fuel may be fed to this fire-pot from a magazine i2, provided with an outlet I3 for directing fuel into the fire-pot and with a lid l4. Surrounding the shell Ill and spaced therefrom is a suitable jacket comprising an inner wall l5 and an outer wall It. This outer wall and the magazine may be suitably heat insulated, if desired, as indicated at 11. This jacket is arranged to contain the fluid medium It! to be heated which, in this case, is water, an inlet for cold water being provided at l9 and an outlet for hot water at 20. A suitable ash pit 2| may be provided below the grate i I having a door 22 with a handle 22a to permit removal of ashes. Air for combustion may be supplied to the ash pit and thence through the grate H to the fuel in the fire-pot by means of the opening 23. 'The products of combustion are withdrawn through the opening 24 and passed to a stack by way of the conduit 25.

An air space 26 is provided between the firepot shell Ill and the inner wall l5 of the water jacket across which heat from the fire-pot is radiated, as described in the co-pending application of Raymond Johnson, Ser. No. 64,835, filed Feb. 20, 1936. Air maybe admitted to the lower portion of this space 26 through the opening 21 and the heated air may be passed by way of the opening 28 into the chamber 29 with which the fiue 25 and the opening 24 communicate. The passage of heated air to a stack for control of natural draft is more particularly described in the above-mentioned co-pending application of Harold J. Rose, Ser. No. 78,549.

The flow of air for combustion purposes and the stream of air to be heated in passageway 26 may be controlled either at the inlet and/or at the outlet of the heating apparatus. A control at the inlet is illustrated in the embodiment shown in Fig. 1 and the two streams of gas are preferably controlled so that when one is checked, the other may fiow unimpeded.

To accomplish this result automatically, a plate 30 may be adjustably mounted over the projecting ends of the conduits 23 and 21by means of the set screws 3|. An arm 32 is fixed to this plate 30 and pivotally supports the damper arm 33 by means of the pin 34. Fixed at the ends of this damper arm 33 are a pair of-rods 35, 36 which are threaded on their free ends and carry the through the conduits 21 and 23, respectively.

These dampers 31, 33 are preferably floatingly thermostatic device, which communicates with a fluid reservoir 40 by means of the tube 4i. One end of the bellows is fixed to the plate Ill and the other end has a rod 42 fixed thereto which is pivotally connected to'the damper arm 33 by the pin 43. The bellows 39 and the reservoir 40 are filled with an expansible fluid and the reservoir 40 is positioned to operate the bellows 39 in accordance with the temperature of the water l8 near the water outlet 20.

In the extreme position illustrated in Fig. 1 the water It is heated to its maximum temperature which, for example, may be 150 F., thus fully expanding bellows 33 to close damper 38 and open damper 31. The fire is thus completely checked and air passed freely into the space 26, thus supplying the stack with ample warm, dry air to preserve a'desirable amount of natural draft ready for instant use.

In the other extreme position, the fire will be on full draft whereas only a minimum quantity of heated air will be supplied byway of the conduit 23 to the stack. In the latter position the products of combustion. serve to maintain the natural draft, and heat intended for they water It is not dissipated. In the intermediate positions varying degrees of control are exercised in accordance with the exacttemperature of the water being heated and undesirable under-heating and over-heating of the water are consequently eliminated in a large extent. Small openings may be provided in the dampers 31 and 38, if desired, to provide for any desired minimum flow of air at all times.

With apparatus such as just described, the dampers control the air stream entering the heater and have the advantage of working in cool, clean air. The combustion products have free access to the stack and any leakage in the lid l4 will serve-to ventilate the fuel magazine since it is under stack draft at all times.

In controlling air at the inlet; however, it is desirable that the ash pit be constructed and main-- tained substantially air tight in order to have the automatic control eifective and to insure against a runaway .fire. To avoid this and to enable the use of an ash pit which is hot air tight, a damper control arrangement such as illustrated in 2-7 may be employed. This arrangement has the further advantages of having the apparatus more compact, rugged, with fewer moving parts, and without thenecessity of remote control. If desired the fuel magazine l2 may be vented to the stack, when employing the dampers shown in Figures 2-7.

With reference to Figs. 2-4, the outlet conduits 24a and 2341 may be provided in substantially the same position as the conduits 24 and 28 illustrated in mg. 1, the inner walls lid and outer walls I60 defining portions of the water jacket for the water II. A chamber 230, common to both conduits 24a and 231;, may be secured to the outer walls "a by means of the bolt 44, or in any other suitable. manner. The upper end of this chamber preferably communicates with conduit 25 which leads to the stack .or chimney. Automatic swinging dampers 45 and 43 may be provided as described in the above-mentioned application of Harold J. Rose, Ser. No. 78,549 to eliminate down drafts, and to provide an inlet for cold air for reducing excessive drafts, respectively. Chamber 29a is provided with a lug or stop 41 on the inside of one wall to support one end of a damper 48 in one of its extreme positions. This damper 48 may be of generally semi-circular shape, as illustrated in. Fig. 3, and is mounted at its straight edge on the rod 49 which is pivotally supported in the walls of chamber 29a.

One end of rod 49 is provided with a short crank arm 50 fixed thereto. The other end of this crank arm 50 is pivotally connected to the bifurcated end of rod 5| by means of pin 52. The other end of rod 5| may be fixed to the inner end of a collapsible bellows 53. The thin walled casing 54 may be filled with an expansible fluid which surrounds the bellows 53. The length 'of crank-arm 50 should be proportioned in accordance with the expansibility of this fiuid. The thin-walled container 54'is preferably mounted in the section 55 of the water jacket and is directly exposed to the heated water in proximity to the water outlet (Fig. 1). It will be readily seen that as the bellows 53 contracts with increased heat of the water I8, and expansion of the fiuid in. casing 54, the damper 48 will be moved to a vertical position, checking the fire and allowing heated air from the passage around the fire-pot to pass freely to the stack through the conduit 23a. In the other extreme position; the heated air in the space around the fire-pot is substantially checked and the full stack draft is supplied to the fuel. A small opening 56 may be provided in the dampen 48 to allow a minimum flow of gases in each of these extreme positions.

A further modification of draft control apparatus is-illustrated in Figures 5 to 7. In this embodiment of the invention, the walls I51) and l6b comprise the water jacket and the products opening 28b and the chamber 291).

A door 56 is preferably arranged in the lower portion of chamber 29b which may be pivoted at'the hinge 51 and normally heldclosed by the spring clip 58. Damper 48a is provided for controlling the fiow of gases and air through the openings 24b and 28b respectively. This damper is preferably similar to damper 48 (Fig. 2) in construction and operation, and is mounted on a rod 43a. Damper 48a may be actuated automatically by expansible fiuid in casing 54a acting through the collapsible bellows 53a, rod 5 la, crank arm 50a and rod 49a as described above in connection with the damper 48,

Directly opposite damper 48a, a second damper 59 is preferably positioned to close an opening 60 in the wall of chamber 231). On its inner surface, damper 59 is provided with a flange 61 to receive and support the upper end of damper 48a in one extreme position. Damper 59 is fixed to a rod 62 which is mounted for rotation in the walls of chamber 231) and actuated by crank arm 63 and rod 64. Rod 64 is connected to the inner end of the bellows 65 and operated by expansible fluid in the casing 66 and surrounding bellows 65 in a manner similar to the operation of the other thermostatic device for damper 48a.

The operation of damper 48a may be adjusted for automatic regulation of the flow of gases and air through the openings 24!: and new the thermostatic control so that the water to be heated does not exceed a temperature of 150 1?. As

long as this control operates satisfactorily and prevents overruns or overheating of the wateiz.

The thermostatic device operating damper 98 may conveniently be set to operate at some temperature above the normal temperature of the water to be heated, such as 170 to 196 F., in order.to minimize the ei'iect of any failure of damper 48a to close tightly. Whenever the water becomes overheated for any-reason, damper W is swung inwardly by its thermostatic device to admit cold air from the room through opening Bil to the stack by way of conduit 25. The amount oiKdraft is reduced by thus cooling the stack'and the flow of combustion gases to the stack is throttled by the damper. In addition, I prefer to arrange damper 59 so that it will cooperate mechanically with damper Na in checking the fire. With these dampers arranged as illustrated in Figure 5-, damper 59, when open, will be pressed against damper Mia with a wedging action that will assist in closing damper 48a tightly.

'With this combination of dampers and the thermostatic devices connected thereto set to operate in tandem, dangerous overheating. is effectively prevented by damper 59 until the cause of the overheating is eliminated. Access to damper 48a may be had by opening door 55 to determine the condition inside the chamber 291) or for adjusting or cleaning the dampers and chamber.

It will be understood that it is preferred, when employing a modification such as illustrated in Figs. 2-7, to provide suitable openings such as shown at 28 and 21 of Fig. 1 which are open at all times. On the other hand, if auxillarycontrol is :necessary, additional dampers may. also be employed at these points.

' By reason of the positioning of dampers 4,8 and 480 with respect to the conduits 24c and 24b, respectively, the most effective control is obtained for the products of combustion froni'the fire-pot.

Many modifications may be employed within the scope of my invention, it being understood thatth'ermostatic devices controlling the damper or dampers may be of any suitable form and provided in'any desired place, such as on or in i the hot water storage tank, or otherpoint in a hot water system. Various other types ofthermostatic regulators may also be employed.

Damper controls such as described and illustrated are also suitable for 'usewith other solid-fuel heaters where a definite relationship between two streams of gas is to be controlled and maintained.

The single damper control illustrated in Figs.

2-! may bevery ,readily adaptedto the inlet for 'the two streams of air with air flowing past the dampers 48- or 48a in either direction.

I Butterfly dampers may also be employed in the embodiment of Fig. '1, instead of the discs 31 .and 38, operated by crank arms attached to rods 3 and 30. Such a modification could be employed at either the outlet or inlet for the gaseous streams. -The terms and expressions which I have employed are used as terms of description and not of second stream of airto be heated out of contact with said fuel, damper means for automatically controlling the flow of one of said streams conversely to the control of the other -of said streams.

2. In heating apparatus having a stream of air for supporting combustion of solid fuel and a second stream of air to be heated out of contact with said fuel for maintaining natural stack draft available when the fire is checked, dampermeans for controlling the flow of said streams, said means being constructed and arranged to simultaneously check one of said streams and release the other.

3. In heating apparatus having a stream of air for supportingcombustion of fuel and a second stream of air to be heated out of contact with said fuel, damper means for controlling the flow of said streams, said means comprising a single damper arranged and constructed to simultaneously check one. of said streams and release the .other.

4. Apparatus for controlling the flow of a plurality of independent streams of gas comprising a conduit, a second conduit opening into said first conduit, and a damper positioned in said first conduit adjacent said second conduit arranged to check the flow of gas through either of said conduits.

5. Apparatus for controlling the flow of a plurality' of independent streams of gas comprising a conduit, a second conduit opening into said first conduit, ,and a damper pivotally mounted in one of said conduits for checking the fiow of gas through either of said conduits.

6. Heating apparatus comprising a solid fuel burning fire-pot for heating a medium, -means for passing products of combustion and 3 allowing the passage of the other of saidgases 'to the stack. a l

., a '7. Heating apparatus comprising-a solid fuel burning fire-pot for heating a liquidmediurn, means for passing products of combustion and 'air heatedby but out of contact with said fuel to a stack, means for checking the flow of either one of said gases while allowing the passage of the other of said gases to the stack, and means for actuating said last named means in accordance with the temperature of said medium.

8. Heating. apparatus comprising a solid fuel burning fire-pot for heating a liquid medium,

means for passing products of combustion and air heated by but out of contact with said fuel to a stack, means for checking the flow of either the other of. said gases to the stack, and thermostatic means for gradually varying said last named means in accordance with the temperatu'reoi'saidmedlum.

' one of. said gases while allowing the passage of i 9. Heating-apparatus for heating a liquid medium comprising conduits for permitting products of combustion and heated air to escape from said apparatus to a flue, thermostatic means operated by the temperature of said medium, and a damper connected to and actuated by said means and arranged to eflectively close either of said conduits.

10. Heating apparatus for heating a fluid medium comprising conduits for-permitting products of combustion and heated air to escape from said apparatus to a flue, thermostatic means operated by the temperature of said medium, and a damper pivotally mounted in one of said conduits for effectively closing either of said conduits, said damper being operated directly by said means.

11. Heating apparatus comprising means for admitting a plurality of separate and independent streams ofair, dampers for effectively closing said means, and an arm supported for pivotal movement carrying said dampers.

12. Heating apparatus comprising means for admitting a plurality of separate and independent streams of air, dampers for effectively closing said means, and an arm supported intermediate its ends for pivotal movement and carrying means for actuating said dampers on each side of the support.

13. Heating apparatus comprising means for admitting a plurality of separate and independent streams of air, dampers for effectively closing said means, and an arm supported for pivotal movement carrying said dampers, said dampers being carried by said arm in such a manner that they are maintained substantially vertical in both open and closed position.

14. Heating apparatus for heating a fluid medium comprising means for admitting two separate and independent streams of air, a pair of dampers for regulating the flow of air through said means, an arm pivotally supported intermediate its ends for actuating said dampers, and thermostatic means for moving said arm in accordance with the temperature of said medium.

15. Heating apparatus comprising a fire-pot, means for the passage of a stream of air for combustion of the fuel in said fire-pot, means for passing products of combustion to a stack, means for the passage of an independent stream of air external to said fire-pot for receiving heat therefrom. out of contact with said fuel, means for passing said independent stream of air after heating to said stack, and temperature controlled means for controlling the flow of said streams of air in a given relation to each other.

16. Heating apparatus comprising a fire-pot, means for passing products of combustion from said fire-pot to a stack, means for controlling the flow of said products of combustion, and damper means operable upon failure of said controlling means to effectively check said flow for introducing cold air into the stack, said damper means being arranged to assist said controlling means mechanically in checking said flow.

17. In heating apparatus having a conduit for passing products of combustion to a stack and a second conduit passing heated air to the stack, a damper for regulating the flow of said products of combustion and said heated air inversely with respect to each other and means supplementing said damper for allowing cold air to pass to said stack and for throttling the flow of combus tion products thereto.

18. In heating apparatus having a conduit for passing products of combustion to a stack and a second conduit passing heated air to the stack, a damper for regulating the flow of said products of combustion and said heated air inversely with respect to each other, and means supplementing said damper for allowing cold air to pass to said stack, said means cooperating with said damper to check the flow of combustion products as said cold air is allowed to pass to the stack.

19. In heating apparatus having a conduit for passing products of combustion to a stack and a second conduit passing heated air to the stack, a damper for regulating the flow of said products of combustion and said heated air inversely with respect to each other, and means supplementing said damper for allowing cold air to pass to said stack, said means being arranged to move said damper to a position checking the flow of combustion products.

20. In heating apparatus having a conduit for passing products of combustion to a stack and a second conduit joining said first conduit for passing heated air to said stack, a damper at the junction of said conduits for regulating the flow of combustion products and heated air inversely with respect to each other, a second damper for admitting cold air to said stack, said second damper being adjacent said first damper and arranged when opening to strike against said first damper so as to move said first damper toward a position checking the flow of combustion products.

21. A solid fuel hot water heater comprising a fire-pot, a conduit for passing products of combustion to a stack, a second conduit for passing air heated by said fire-pot to said stack, means for regulating the flow of combustion products inversely to the fiow of heated air, damper means for admitting cold air to the stack, means responsive to the temperature of the water for operating said regulating means, and means responsive to a higher temperature of said water than said first responsive means for actuatingsaid damper means.

. HILMAR R. HAGEN. 

